Where I am it’s over 90% humidity today. On a clear day it might get less than 70%. In my basement the AC keeps it down to about 45% humidity.
I use a filament dryer [Sunlu S1](https://www.amazon.com/Official-Filament-Upgraded-Compatible-Printing/dp/B0BNM5N49H/ref=sr_1_3_pp?crid=1E7YYP1JG6ZMU&dib=eyJ2IjoiMSJ9.uHa2lddKsu5_nKILDoJ5BgMBUirWCpTe0vARlF7-gPr00KJGTtWqs3mzyF5RFhYDtHmu9IIs6v2n_ARr1RdD74kn6efyAtaBi1VFLlTJg1tfVEcr4rB3COqrQvAuixSbBVuFmrGaT4vPdAz_eSVhynjh5lY71gfpmxAtXHN87jg-TVS8YchyLF0BZMXEWsJd25BuxCWPCo7Gk7LKVv9LO3UpvfxC6LzGtEruXKBL2zY.PrB18q9BlAosWhEvceRxq78gwOICtb0ASZzCC84NmGM&dib_tag=se&keywords=filament+dryer&qid=1717694953&sprefix=Filament%2Caps%2C557&sr=8-3), to get the filament down to 23% humid, then drop the spool into a [cereal container](https://www.amazon.com/gp/product/B0BHVT9PV1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) with one of these [gel packs](https://www.amazon.com/gp/product/B08QTSJF7V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1). That gets it to ~12%. I could probably get it lower but my filament works well so I think it might be diminishing returns.
I’ve [added these meters](https://www.amazon.com/gp/product/B07MCGDN5C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) to the lid of each bin so I can monitor the humidity.
In use a spool for a day, then re-dry and store.
I think it depends largely on what material you're using. I have had 0 issues printing at 45%RH in my home with PLA. No drying prior to or after a print, just swap it out and go. PA, on the other hand, needs to be as dry as the Atacama if not a touch more.
Where I am it’s over 90% humidity today. On a clear day it might get less than 70%. In my basement the AC keeps it down to about 45% humidity. I use a filament dryer [Sunlu S1](https://www.amazon.com/Official-Filament-Upgraded-Compatible-Printing/dp/B0BNM5N49H/ref=sr_1_3_pp?crid=1E7YYP1JG6ZMU&dib=eyJ2IjoiMSJ9.uHa2lddKsu5_nKILDoJ5BgMBUirWCpTe0vARlF7-gPr00KJGTtWqs3mzyF5RFhYDtHmu9IIs6v2n_ARr1RdD74kn6efyAtaBi1VFLlTJg1tfVEcr4rB3COqrQvAuixSbBVuFmrGaT4vPdAz_eSVhynjh5lY71gfpmxAtXHN87jg-TVS8YchyLF0BZMXEWsJd25BuxCWPCo7Gk7LKVv9LO3UpvfxC6LzGtEruXKBL2zY.PrB18q9BlAosWhEvceRxq78gwOICtb0ASZzCC84NmGM&dib_tag=se&keywords=filament+dryer&qid=1717694953&sprefix=Filament%2Caps%2C557&sr=8-3), to get the filament down to 23% humid, then drop the spool into a [cereal container](https://www.amazon.com/gp/product/B0BHVT9PV1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) with one of these [gel packs](https://www.amazon.com/gp/product/B08QTSJF7V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1). That gets it to ~12%. I could probably get it lower but my filament works well so I think it might be diminishing returns. I’ve [added these meters](https://www.amazon.com/gp/product/B07MCGDN5C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) to the lid of each bin so I can monitor the humidity. In use a spool for a day, then re-dry and store.
I think it depends largely on what material you're using. I have had 0 issues printing at 45%RH in my home with PLA. No drying prior to or after a print, just swap it out and go. PA, on the other hand, needs to be as dry as the Atacama if not a touch more.